Is it valid for me to backup my games through Steam (I created a backup on my hard drive), move the backup to the new system, and restore them?

It *does* seem to work, but I've had some strange issues with games terminating abruptly and Windows 7 saying the game has stopped working. It's happened with both Dead Island & Portal 2 (actually Portal 2 just blipped out to the desktop, no "crash" so to speak).

I haven't gotten a chance to do much, but on the night I posted that, I uninstalled Steam & all the games, reinstalled Steam, and then downloaded Portal 2 again.

I haven't played it yet (been busy with work unfortunately) but tonight I got back to it, and am going to try it.

I did a validation on the game cache, but it consistently comes up with that 1 file needs to be downloaded again. What gives with that?

Off to try the game again now anyway...

OK, well, I just played it for about 20 minutes. Couldn't really last longer than about 5 or so before. I need to follow up, I did read in another post online about virtual CD programs causing these types of issues on Windows 7; I did uninstall mine before trying. So I kind of have 2 variables now.